I guess this is who he would be if the mother of Jesus is not the mother of God.
Precisely! It is our weak human nature that is never fully convinced unless we see proof (miracles) and, even then, there are still doubters. In the Maronite Catholic Church, throughout the season of Lent, we hear the miracle stories of Jesus. They begin with the Miracle at Cana and build gradually, each week: the Hemorrhaging Woman, the Paralytic, Bartimaeus the Blind, etc. and culminate this Saturday with the raising of Lazarus from the dead, the greatest miracle of all. No wonder throngs gathered on Sunday, waving palms and olive branches to welcome Jesus to Jerusalem. Words have meaning and some were persuaded by what Jesus said but it was the Miracles (actions) that spoke to the populace, convincing them that he was the Messiah.
Ironically, those who greeted him en route with shouts of "Hosanna!" would later shout "Crucify him!" on Good Friday. Ultimately, for those who believe, no proof is necessary whereas for those who do not, no proof is sufficient.